drivers/watchdog/it8712f_wdt.c

   1 /*
   2  *      IT8712F "Smart Guardian" Watchdog support
   3  *
   4  *      Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
   5  *
   6  *      Based on info and code taken from:
   7  *
   8  *      drivers/char/watchdog/scx200_wdt.c
   9  *      drivers/hwmon/it87.c
  10  *      IT8712F EC-LPC I/O Preliminary Specification 0.8.2
  11  *      IT8712F EC-LPC I/O Preliminary Specification 0.9.3
  12  *
  13  *      This program is free software; you can redistribute it and/or
  14  *      modify it under the terms of the GNU General Public License as
  15  *      published by the Free Software Foundation; either version 2 of the
  16  *      License, or (at your option) any later version.
  17  *
  18  *      The author(s) of this software shall not be held liable for damages
  19  *      of any nature resulting due to the use of this software. This
  20  *      software is provided AS-IS with no warranties.
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/init.h>
  26 #include <linux/miscdevice.h>
  27 #include <linux/watchdog.h>
  28 #include <linux/notifier.h>
  29 #include <linux/reboot.h>
  30 #include <linux/fs.h>
  31 #include <linux/pci.h>
  32 #include <linux/spinlock.h>
  33
  34 #include <asm/uaccess.h>
  35 #include <asm/io.h>
  36
  37 #define NAME "it8712f_wdt"
  38
  39 MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
  40 MODULE_DESCRIPTION("IT8712F Watchdog Driver");
  41 MODULE_LICENSE("GPL");
  42 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
  43
  44 static int max_units = 255;
  45 static int margin = 60;         /* in seconds */
  46 module_param(margin, int, 0);
  47 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
  48
  49 static int nowayout = WATCHDOG_NOWAYOUT;
  50 module_param(nowayout, int, 0);
  51 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
  52
  53 static struct semaphore it8712f_wdt_sem;
  54 static unsigned expect_close;
  55 static spinlock_t io_lock;
  56 static unsigned char revision;
  57
  58 /* Dog Food address - We use the game port address */
  59 static unsigned short address;
  60
  61 #define REG             0x2e    /* The register to read/write */
  62 #define VAL             0x2f    /* The value to read/write */
  63
  64 #define LDN             0x07    /* Register: Logical device select */
  65 #define DEVID           0x20    /* Register: Device ID */
  66 #define DEVREV          0x22    /* Register: Device Revision */
  67 #define ACT_REG         0x30    /* LDN Register: Activation */
  68 #define BASE_REG        0x60    /* LDN Register: Base address */
  69
  70 #define IT8712F_DEVID   0x8712
  71
  72 #define LDN_GPIO        0x07    /* GPIO and Watch Dog Timer */
  73 #define LDN_GAME        0x09    /* Game Port */
  74
  75 #define WDT_CONTROL     0x71    /* WDT Register: Control */
  76 #define WDT_CONFIG      0x72    /* WDT Register: Configuration */
  77 #define WDT_TIMEOUT     0x73    /* WDT Register: Timeout Value */
  78
  79 #define WDT_RESET_GAME  0x10
  80 #define WDT_RESET_KBD   0x20
  81 #define WDT_RESET_MOUSE 0x40
  82 #define WDT_RESET_CIR   0x80
  83
  84 #define WDT_UNIT_SEC    0x80    /* If 0 in MINUTES */
  85
  86 #define WDT_OUT_PWROK   0x10
  87 #define WDT_OUT_KRST    0x40
  88
  89 static int
  90 superio_inb(int reg)
  91 {
  92         outb(reg, REG);
  93         return inb(VAL);
  94 }
  95
  96 static void
  97 superio_outb(int val, int reg)
  98 {
  99         outb(reg, REG);
 100         outb(val, VAL);
 101 }
 102
 103 static int
 104 superio_inw(int reg)
 105 {
 106         int val;
 107         outb(reg++, REG);
 108         val = inb(VAL) << 8;
 109         outb(reg, REG);
 110         val |= inb(VAL);
 111         return val;
 112 }
 113
 114 static void
 115 superio_outw(int val, int reg)
 116 {
 117         outb(reg++, REG);
 118         outb((val >> 8) & 0xff, VAL);
 119         outb(reg, REG);
 120         outb(val & 0xff, VAL);
 121 }
 122
 123 static inline void
 124 superio_select(int ldn)
 125 {
 126         outb(LDN, REG);
 127         outb(ldn, VAL);
 128 }
 129
 130 static inline void
 131 superio_enter(void)
 132 {
 133         spin_lock(&io_lock);
 134         outb(0x87, REG);
 135         outb(0x01, REG);
 136         outb(0x55, REG);
 137         outb(0x55, REG);
 138 }
 139
 140 static inline void
 141 superio_exit(void)
 142 {
 143         outb(0x02, REG);
 144         outb(0x02, VAL);
 145         spin_unlock(&io_lock);
 146 }
 147
 148 static inline void
 149 it8712f_wdt_ping(void)
 150 {
 151         inb(address);
 152 }
 153
 154 static void
 155 it8712f_wdt_update_margin(void)
 156 {
 157         int config = WDT_OUT_KRST | WDT_OUT_PWROK;
 158         int units = margin;
 159
 160         /* Switch to minutes precision if the configured margin
 161          * value does not fit within the register width.
 162          */
 163         if (units <= max_units) {
 164                 config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
 165                 printk(KERN_INFO NAME ": timer margin %d seconds\n", units);
 166         } else {
 167                 units /= 60;
 168                 printk(KERN_INFO NAME ": timer margin %d minutes\n", units);
 169         }
 170         superio_outb(config, WDT_CONFIG);
 171
 172         if (revision >= 0x08)
 173                 superio_outw(units, WDT_TIMEOUT);
 174         else
 175                 superio_outb(units, WDT_TIMEOUT);
 176 }
 177
 178 static int
 179 it8712f_wdt_get_status(void)
 180 {
 181         if (superio_inb(WDT_CONTROL) & 0x01)
 182                 return WDIOF_CARDRESET;
 183         else
 184                 return 0;
 185 }
 186
 187 static void
 188 it8712f_wdt_enable(void)
 189 {
 190         printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
 191         superio_enter();
 192         superio_select(LDN_GPIO);
 193
 194         superio_outb(WDT_RESET_GAME, WDT_CONTROL);
 195
 196         it8712f_wdt_update_margin();
 197
 198         superio_exit();
 199
 200         it8712f_wdt_ping();
 201 }
 202
 203 static void
 204 it8712f_wdt_disable(void)
 205 {
 206         printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
 207
 208         superio_enter();
 209         superio_select(LDN_GPIO);
 210
 211         superio_outb(0, WDT_CONFIG);
 212         superio_outb(0, WDT_CONTROL);
 213         superio_outb(0, WDT_TIMEOUT);
 214
 215         superio_exit();
 216 }
 217
 218 static int
 219 it8712f_wdt_notify(struct notifier_block *this,
 220                     unsigned long code, void *unused)
 221 {
 222         if (code == SYS_HALT || code == SYS_POWER_OFF)
 223                 if (!nowayout)
 224                         it8712f_wdt_disable();
 225
 226         return NOTIFY_DONE;
 227 }
 228
 229 static struct notifier_block it8712f_wdt_notifier = {
 230         .notifier_call = it8712f_wdt_notify,
 231 };
 232
 233 static ssize_t
 234 it8712f_wdt_write(struct file *file, const char __user *data,
 235         size_t len, loff_t *ppos)
 236 {
 237         /* check for a magic close character */
 238         if (len) {
 239                 size_t i;
 240
 241                 it8712f_wdt_ping();
 242
 243                 expect_close = 0;
 244                 for (i = 0; i < len; ++i) {
 245                         char c;
 246                         if (get_user(c, data+i))
 247                                 return -EFAULT;
 248                         if (c == 'V')
 249                                 expect_close = 42;
 250                 }
 251         }
 252
 253         return len;
 254 }
 255
 256 static int
 257 it8712f_wdt_ioctl(struct inode *inode, struct file *file,
 258         unsigned int cmd, unsigned long arg)
 259 {
 260         void __user *argp = (void __user *)arg;
 261         int __user *p = argp;
 262         static struct watchdog_info ident = {
 263                 .identity = "IT8712F Watchdog",
 264                 .firmware_version = 1,
 265                 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 266         };
 267         int value;
 268
 269         switch (cmd) {
 270         default:
 271                 return -ENOTTY;
 272         case WDIOC_GETSUPPORT:
 273                 if (copy_to_user(argp, &ident, sizeof(ident)))
 274                         return -EFAULT;
 275                 return 0;
 276         case WDIOC_GETSTATUS:
 277                 superio_enter();
 278                 superio_select(LDN_GPIO);
 279
 280                 value = it8712f_wdt_get_status();
 281
 282                 superio_exit();
 283
 284                 return put_user(value, p);
 285         case WDIOC_GETBOOTSTATUS:
 286                 return put_user(0, p);
 287         case WDIOC_KEEPALIVE:
 288                 it8712f_wdt_ping();
 289                 return 0;
 290         case WDIOC_SETTIMEOUT:
 291                 if (get_user(value, p))
 292                         return -EFAULT;
 293                 if (value < 1)
 294                         return -EINVAL;
 295                 if (value > (max_units * 60))
 296                         return -EINVAL;
 297                 margin = value;
 298                 superio_enter();
 299                 superio_select(LDN_GPIO);
 300
 301                 it8712f_wdt_update_margin();
 302
 303                 superio_exit();
 304                 it8712f_wdt_ping();
 305                 /* Fall through */
 306         case WDIOC_GETTIMEOUT:
 307                 if (put_user(margin, p))
 308                         return -EFAULT;
 309                 return 0;
 310         }
 311 }
 312
 313 static int
 314 it8712f_wdt_open(struct inode *inode, struct file *file)
 315 {
 316         /* only allow one at a time */
 317         if (down_trylock(&it8712f_wdt_sem))
 318                 return -EBUSY;
 319         it8712f_wdt_enable();
 320
 321         return nonseekable_open(inode, file);
 322 }
 323
 324 static int
 325 it8712f_wdt_release(struct inode *inode, struct file *file)
 326 {
 327         if (expect_close != 42) {
 328                 printk(KERN_WARNING NAME
 329                         ": watchdog device closed unexpectedly, will not"
 330                         " disable the watchdog timer\n");
 331         } else if (!nowayout) {
 332                 it8712f_wdt_disable();
 333         }
 334         expect_close = 0;
 335         up(&it8712f_wdt_sem);
 336
 337         return 0;
 338 }
 339
 340 static const struct file_operations it8712f_wdt_fops = {
 341         .owner = THIS_MODULE,
 342         .llseek = no_llseek,
 343         .write = it8712f_wdt_write,
 344         .ioctl = it8712f_wdt_ioctl,
 345         .open = it8712f_wdt_open,
 346         .release = it8712f_wdt_release,
 347 };
 348
 349 static struct miscdevice it8712f_wdt_miscdev = {
 350         .minor = WATCHDOG_MINOR,
 351         .name = "watchdog",
 352         .fops = &it8712f_wdt_fops,
 353 };
 354
 355 static int __init
 356 it8712f_wdt_find(unsigned short *address)
 357 {
 358         int err = -ENODEV;
 359         int chip_type;
 360
 361         superio_enter();
 362         chip_type = superio_inw(DEVID);
 363         if (chip_type != IT8712F_DEVID)
 364                 goto exit;
 365
 366         superio_select(LDN_GAME);
 367         superio_outb(1, ACT_REG);
 368         if (!(superio_inb(ACT_REG) & 0x01)) {
 369                 printk(KERN_ERR NAME ": Device not activated, skipping\n");
 370                 goto exit;
 371         }
 372
 373         *address = superio_inw(BASE_REG);
 374         if (*address == 0) {
 375                 printk(KERN_ERR NAME ": Base address not set, skipping\n");
 376                 goto exit;
 377         }
 378
 379         err = 0;
 380         revision = superio_inb(DEVREV) & 0x0f;
 381
 382         /* Later revisions have 16-bit values per datasheet 0.9.1 */
 383         if (revision >= 0x08)
 384                 max_units = 65535;
 385
 386         if (margin > (max_units * 60))
 387                 margin = (max_units * 60);
 388
 389         printk(KERN_INFO NAME ": Found IT%04xF chip revision %d - "
 390                 "using DogFood address 0x%x\n",
 391                 chip_type, revision, *address);
 392
 393 exit:
 394         superio_exit();
 395         return err;
 396 }
 397
 398 static int __init
 399 it8712f_wdt_init(void)
 400 {
 401         int err = 0;
 402
 403         spin_lock_init(&io_lock);
 404
 405         if (it8712f_wdt_find(&address))
 406                 return -ENODEV;
 407
 408         if (!request_region(address, 1, "IT8712F Watchdog")) {
 409                 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
 410                 return -EBUSY;
 411         }
 412
 413         it8712f_wdt_disable();
 414
 415         sema_init(&it8712f_wdt_sem, 1);
 416
 417         err = register_reboot_notifier(&it8712f_wdt_notifier);
 418         if (err) {
 419                 printk(KERN_ERR NAME ": unable to register reboot notifier\n");
 420                 goto out;
 421         }
 422
 423         err = misc_register(&it8712f_wdt_miscdev);
 424         if (err) {
 425                 printk(KERN_ERR NAME
 426                         ": cannot register miscdev on minor=%d (err=%d)\n",
 427                         WATCHDOG_MINOR, err);
 428                 goto reboot_out;
 429         }
 430
 431         return 0;
 432
 433
 434 reboot_out:
 435         unregister_reboot_notifier(&it8712f_wdt_notifier);
 436 out:
 437         release_region(address, 1);
 438         return err;
 439 }
 440
 441 static void __exit
 442 it8712f_wdt_exit(void)
 443 {
 444         misc_deregister(&it8712f_wdt_miscdev);
 445         unregister_reboot_notifier(&it8712f_wdt_notifier);
 446         release_region(address, 1);
 447 }
 448
 449 module_init(it8712f_wdt_init);
 450 module_exit(it8712f_wdt_exit);